Meat-curing salt composition



United States Patent MEAT-CURlNG SALT COMPOSITION Lloyd A. Hall, Chicago, Ill., assignor to The Grifiith Laboratories, Inc, Chicago, 111., a corporation of [H1- nois No Drawing. Application July 1, 1955, Serial No. 519,617

Claims. (Cl. 99--222) The present invention relates to curing salt composi tions, and more particularly to the production of an improved composition of sodium chloride crystals housing alkali metal salt of either one or both of nitric acid and nitrous acid, and especially to a non-caking composition.

The fiash-drying of a solution of sodium chloride containing alkali metal nitrite or alkali metal nitrate, or both, to form sodium chloride crystals housing said other salt as heart-like centers, is fully described in U. S. patents to Griffith No. 2,054,624 and No. 2,054,626, and to Hall No. 2,145,417, No. 2,668,770 and No. 2,668,771.

The basic composition is first described in the said Grifiith patents wherein it is disclosed that such crystals may be formed by flash-drying, as on heated rolls, a strong solution of sodium chloride containing a minor proportion of the nitrogen-containing meat-curing salts. The resulting crystals have the characteristic cubic form of sodium chloride crystals, but under the microscope there may be seen within them heart-like centers which are the nitrogen-containing curing salt. It is also disclosed that the rapid crystallization produces an unstable mass of crystals including a very small quantity of water which is gradually decreased or increased according to equilibrium content with the environment. As formed, the environment is very humid so that the initial change is release of moisture. This takes place in the drums in which the material is stored, and as a result, the mass tends to cake on standing after the initial packaging.

The process and the character of the crystals are more scientifically expounded in the publication of Clark and Hall, Industrial and Engineering Chemistry, vol. 33, p. 98 (1941). As shown in said publication, all of the curing salt is included when the amount is small, and the included amount varies somewhat with the proportions in which the nitrite salt and nitrate salt are present. The

following illustrates:

Table I Percent Percent Percent Percent NaN Oz NaNOa NaCl Inclusion Since these crystals are manufactured and variously stored before use in the meat-packing industry, it has been a commercial disadvantage that the product gradually cakes in the shipping container. Numerous expedients have been tried to prevent the caking, but only to a degree has it been minimized, as evidenced by prolonging the time until caking occurs. One of the earliest ICC methods of minimizing the caking is described in the Griffith patents wherein a hygroscopic agent is added, such as corn sugar or glycerine, which is believed to take up the water as it is released from the crystals, and preferentially to take it up from the atmosphere, and thus pro vide an aqueous partition between the crystals.

it has been established that the caking is due in part at least to the initial liberation of water from the crystals, and not wholly from the absorption of moisture from the atmosphere, which commonly is the cause of caking in many salt compositions.

The above-cited patents all disclose the problem of caking and various ways to minimize it. Hall No. 2,145,417, for example, teaches that when commercial corn sugar is used, with or without glycerine, as a hygroscopic agent, the caking is minimized, but that the nitrite value is lowered on aging. Because of a. trace of acidity in commercial corn sugar, Hall stabilized the composition with respect to nitrite by adding a buffering agent to insure a pH value not below 7.4. Sodium carbonate, sodium bicarbonate and disodium phosphate are named as suitable buffering agents. A pH of the solution above 7.4 and upwardly to values as high as 10.3 does not affect the quality of the solution to form jacketed crystals, nor does it operate to prevent caking.

The Hall Patents No. 2,668,770 and No. 2,668,771 also refer to the caking problem and disclose the use of hygroscopic agents to minimize it. The patents name specifically corn sugar, glycerine, sorbitol and propylene glycol. No. 2,668,770 describes the removal of hardness from the water employed in the process, by use of the ionexchange procedures. Elimination of the hardness in no way minimizes the caking, and the product so produced still required the use of hygroscopic agent to minimize caking. Hall Patent No. 2,668,771 is based upon the discovery that traces of certain metallic cations function as oxidation catalysts leading to slow conversion of nitrite salt to nitrate salt, and to remedy this defect, the solution, normally containing such cations, is treated with a small but sequestering amount of poly/phosphate salt, such as sodium tripolyphosphate, to capture such metal cations and render them inelfective as catalysts. This special treatment of the water in no way reduces the tendency to cake, nor eliminates the necessity to use hygro scopic agent.

Although various hygroscopic agents minimize rather than prevent the caking of the above-described compositions, it has not been found that the quantity of such agent may be increased within practical ranges to prevent caking. The present invention is based upon the discovery that the compositions containing the hygroscopic agent may be greatly improved and the caking may be further delayed and even prevented by the inclusion of a small quantity of a newly found agent present in the solution to be flash-dried.

It is, therefore, an object of the invention to make an improved curing salt composition of the type having sodium chloride crystals housing nitrogen-containing curing salt.

It is a particular object to minimize and even prevent the caking of such curing salt composition.

It is also an object to improve the physical character of the composition as originally formed and to retain that character in storage against change by caking.

In the various processes described in the above-cited in a small amount in the solution to be flash-dried, the crystals are initially more powdery in character, and flow like water, with a greatly lessened or lost tendency to cake generally proportional to the amount of tartrate salt preseat. The resulting non-caking compositions retain the ability to flow like water. i

Whether or not a composition cakes is a matter relative to timeand' also storage conditions. Initially, the composition is a mass of free-flowing crystals. The prior art compositions, even though minimized in the tendency to cake byinclusion of a hygroscopic agent, have caked as early as two weeks. A suitable commercial composition should be no n cakingduring the period from manufacture'to consumption of the contents of a container in which it is shipped.

The compositions may be varied for different conditions. For example, whenthe drums are to be stored in a warehouse, the composition should remain free-flowing during the storage period. When drums are not stored in a warehouse, the composition is usually consumed in froir i 'nfO to 69 days after manufacture, and as a safety factor should be free-flowing for at least 90 days. Also, there are consumers located close to the place of manufacture who use the product within a much shorter time following manufacture.

In accordance with the present invention, the amount of alkali metal tartrate included in the composition is varied in accordance with the expected conditions of storage before consumption. In general, it has been found that the inclusion of alkali metal tartrate in amount upwardly from 0.5%, calculated as sodium tartrate dihydrate, adds greatly to the non-caking life of the composition otherwise containing hygroscopic agent. Amounts of alkali metal tartrate above 2.5% calculated as sodium tartrate dihydrate are not required for present-day commercial practices. For the average user, amounts in the range from 1.5% to 2% are suitable and are preferred, but it is to be understood that the invention contemplates using any amount which adds to the non-caking life of a composition otherwise without it. When the anti-caking agents in a composition consist of a hygroscopic agent and alkali metal tartrate, the invention contemplates that there be alkali metal tartrate present at least in amount equivalent to (2.5% of sodium tartrate dihydrate. In the absence of the hygroscopic agent, the same amounts of alkali metal tartrate are not effective, leading to the con clusion that the hygroscopicagent and the alkali metal tartrate are synergistic.

There are compositions in which less than said 0.5% may be employed, but they involve the presence of a third type of anti-caking agent as certain salt of phosphoric acid. For example, trisodium phosphate and disodium phosphate are effective asan 'anti-oaking agent singly and in combination, and alkalimetal tartrate may be used witheach' or both to add to the anti-caking function.

' In carrying out the invention, the various compositions known and commercially made need not'be changed except by the addition of alkali metal tartrate in substitution for part of the sodium chloride. The alkali metal tartrate may be either dissolved as an ingredient in the solution which is *to be flash-dried, or it may be formed from tartaric acid or an alkali metal bitartrate, for example, potassium acid tartrate, and a suitable alkali agent in the final solution or in the course of formulating the final solution. Suitable alkaline agents are the hydroxides and carbonates'of sodium or potassium, and trisodium phosphate.

"In' the forming the final solution, any one or more of the various alkaline agents used in making the solution should be present in quantity to give a desirable pH of at least 7.4 to assure retention of nitrite value.

The invention is illustrated by variations in two basic compositions of which the salt ingredients and the proportions thereof to each other are Well established in commercial uses. These are shown in Table II.

tit)

T able II [Parts in pounds] 1 The amount given is decreased by the amount of material added in the examples below.

In the following examples, the sodium chloride and the sodium or potassium carbonate are dissolved in the water, the tartaric acid added, and then the nitrite and nitrate salts added. The heated solution is then run onto slowly revolving drums heated to a temperature in the range from 310 F. to 330 F. Powdery crystals are scraped from the rolls and conveyed by worm-screw through a cooling tunnel and packed into drums holding about 300 pounds, with the crystals at or below room temperature.

No absolute measure of the desired efiect has been found and only a general estimate from numerous batches has been made. Temperature and humidity differences at the time of manufacture, and also during the storage period, are influential, and in the absence of controlled surroundings, exact values are difficult to secure.

The following Table III gives the data as follows:

Column 1: Example number.

Column 2: Formula of Table II.

Column 3: Quantity of sodium carbonate.

Column 4: Quantity of anhydrous tartaric acid.

Column 5: Percent equivalent of sodium tartrate dihydrate.

Column 6: Comment on general extent of non-caking life.

Table III Example For Per- Comment mula 1b. oz. 1b. oz. cont 1 7 14 9 1 0.5 3 to 3 5 weeks 1 15 11 18 2 1.0 1 to 1.5 months 1 23 12 27 3 1. 5 3 months. 1 31 6 36 4 2.0 3.5 months 1 39 4 45 5 2. 5 D0. 2 7 14 9 1 0.5 3 to 3.5 Weeks. 2 15 11 18 2 1.0 1 to 1.5 months. 2 23 I2 27 3 1. 5 3 months 2 31 6 36 4 2.0 3.5 months 10 2 39 4 t5 5 2. 5 D0. Oontr01 1 ....1 0 2 weeks.

D0..." 2 0 Do.

In the foregoing examples, the glycerine as the hygroscopic agent may be replaced in Whole or in part by an equal weight of either corn sugar, or propylene glycol or sorbitol, or a mixture of such agents, with substantially the same results as described. The hygroscopic agent has anti-caking properties only to a degree such that increasing itscontent does not add to the effect. The presence of a small amount of alkali metal tartrate adds greatly to the effect of the hygroscopic agent, but in the absence of the latter, it has little effect to minimize caking. Accordingly, the combination of the alkali metal tartrate and of hygroscopic agentis a synergistic one.

Whether or not the sodium or the potassium tartrate is used seems to make no difference. The predominance of sodium ions in the solution is believed ultimately to form a predominance of sodium tartrate in the final product.

From the foregoing description and explanation, it will be apparent that the invention may be practiced with numerous variations not limited to the precise illustrations herein given, and such changes and modifications are contemplated as falling Within the scope of the invention as expressed in the appended claims.

I claim:

1. A curing salt composition consisting of the flashdried crystals of an aqueous solution having a pH not under 7.4 and having solute consisting essentially of a major portion of sodium chloride, a minor portion of curing salt selected from the group consisting of alkali metal nitrite, alkali metal nitrate, and mixtures thereof, and a small quantity of anti-caking material comprising a hygroscopic agent and at least 0.5% by Weight of alkali metal tartrate calculated as sodium tartrate dihydrate.

2. The product of claim 1 in which the hygroscopic agent is glycerine.

3. The product of claim 1 in which all the salts are sodium salts.

4. The product of claim 3 in which the hygroscopic agent is glycerine.

5. The product of claim 3 wherein said equivalent of sodium tartrate dihydrate is present in amount in the range from 1.5% to 2.5%.

6. The product of claim 5 in which the hygroscopic agent is glycerine.

7. The method which comprises forming a solution at a pH not under 7.4 containing alkali metal tartrate, sodiurn chloride, hygroscopic material, and curing salt selected from the group consisting of alkali metal nitrite, alkali metal nitrate, and mixtures thereof, the curing salt being present in sufficiently small amount so that a major portion thereof will be jacketed by the sodium chloride in the hereinafter-mentioned flash-drying, and the alkali metal tartrate calculated as sodium tartrate dihydrate being present in amount upwardly from about 0.5% of the solid content of said solution, and flash-drying the said solution.

8. The method of claim 7 in which all the salts are sodium salts.

9. The method which comprises forming a solution at a pH not under 7.4 consisting essentially of alkali metal tartrate, sodium chloride, glycerine, and curing salt selected from the group consisting of alkali metal nitrite, alkali metal nitrate, and mixtures thereof, the curing salt being present in sufficiently small amount so that a major portion thereof will be jacketed by the sodium chloride in the hereinafter-mentioned flash-drying, and the alkali metal tartrate calculated as sodium tartrate dihydrate being present in amount upwardly from 0.5% of the solid content of said solution, and flash-drying the said solution.

10. The method which comprises forming a solution at a pH not under 7.4 consisting essentially of sodium tar trate, sodium chloride, glycerine, and curing salt consisting of sodium nitrite and sodium nitrate, the curing salt being present in sufiiciently small amount so that a major portion thereof will be jacketed by the sodium chloride in the hereinafter-mentioned flash-drying, and the sodium tartrate calculated as dihydrate being present in amount upwardly from 0.5 of the solid content of said solution, and flash-drying the said solution.

References Cited in the file of this patent UNITED STATES PATENTS 2,117,478 Hall May 17, 1938 2,145,417 Hall Jan. 31, 1939 2,668,771 Hall Feb. 9, 1954 

1. A CURING SALT COMPOSITION CONSISTING OF THE FLASHDRIED CRYSTALS OF AN AQUEOUS SOLUTION HAVING A PH NOT UNDER 7.4 AND HAVING SOLUTE CONSISTING ESSENTIALLY OF A MAJOR PORTION OF SODIUM CHLORIDE, A MINOR PORTION OF CURING SALT SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL NITRITE, ALKALI METAL NITRATE, AND MIXTURES THEREOF, AND A SMALL QUANTITY OF ANTI-CAKING MATERIAL COMPRISING A HYGROSCOPIC AGENT AND AT LEAST 0.5% BY WEIGHT OF ALKALI METAL TARTRATE CALCULATED AS SODIUM TARTRATE DIHYDRATE. 